MPICH2, at least 1.0.5, has a more specific way to ignore the SEEK_* issue. What PETSc is currently doing is just completelly skipping the #include of MPI C++ bindings. In OpenMPI, they try hard to solve this issue and not just generate an error like MPICH2, however, compilation time is (about 4x) increased as they have to include <iostream>. I believe doing #define MPICH_SKIP_MPICXX #define OMPI_SKIP_MPICXX #include <mpi.h> Should always work and then PETSc follows the same path for both MPI's. Of course, if users want to use C++ bindings, then they have to #include <mpi.h> before #include <petsc.h>, but it's up to them to solve the issues with MPICH2. On 9/10/07, Barry Smith <[email protected]> wrote:

Actually it is the MPI standard and C++ namespaces etc that cause tis funny problem, MPICH just picked a particular work-around. I do not know what work around, if any, OpenMPI used.

Barry

On Mon, 10 Sep 2007, Matthew Knepley wrote:

...

Not sure. This only happens because MPICH does funny things with SEEK_SET.

Matt

On 9/10/07, Lisandro Dalcin <[email protected]> wrote:

...

We currently do the following in petsc.h

#define MPICH_SKIP_MPICXX 1 #include "mpi.h"

Should do the same for OpenMPI ?

-- Lisandro Dalc�n --------------- Centro Internacional de M�todos Computacionales en Ingenier�a (CIMEC) Instituto de Desarrollo Tecnol�gico para la Industria Qu�mica (INTEC) Consejo Nacional de Investigaciones Cient�ficas y T�cnicas (CONICET) PTLC - G�emes 3450, (3000) Santa Fe, Argentina Tel/Fax: +54-(0)342-451.1594

-- Lisandro Dalc�n --------------- Centro Internacional de M�todos Computacionales en Ingenier�a (CIMEC) Instituto de Desarrollo Tecnol�gico para la Industria Qu�mica (INTEC) Consejo Nacional de Investigaciones Cient�ficas y T�cnicas (CONICET) PTLC - G�emes 3450, (3000) Santa Fe, Argentina Tel/Fax: +54-(0)342-451.1594